Dropwizard GELF

Addon for Dropwizard adding support for logging to a GELF-enabled server like Graylog2 or logstash using the GELF appender for Logback.

Usage

The Dropwizard GELF provides an AppenderFactory which is automatically registered in Dropwizard and will send log messages directly to your configured GELF-enabled server.

Logging startup errors to Graylog2

In order to log startup errors (i. e. before the GelfAppenderFactory has been properly initialized) to a GELF-enabled server, the Dropwizard application has to run GelfBootstrap.bootstrap() in its main method and set a custom UncaughtExceptionHandler for the main thread.

public static void main(String[] args) throws Exception {
    GelfBootstrap.bootstrap(NAME, GELF_HOST, GELF_PORT, false);
    Thread.currentThread().setUncaughtExceptionHandler(UncaughtExceptionHandlers.systemExit());

    new MyDropwizardApplication().run(args);
}

Configuration

The Logback GELF appender can be configured using the provided GelfConfiguration class which basically mirrors the appender configuration outlined in logback-gelf README.

Your YAML configuration could include the following snippet to configure the GelfLoggingBundle:

appenders:
  - type: console
  - type: gelf
    host: localhost
    # facility: MyApplication
    # threshold: ALL
    # host: localhost
    # port: 12201
    # useLoggerName: true
    # useThreadName: true
    # useMarker: false
    # serverVersion: 0.9.6
    # chunkThreshold: 1000
    # messagePattern: %m%rEx
    # shortMessagePattern: %.-100(%m%rEx)
    # hostName: hostname
    includeFullMDC: true
    additionalFields:
      userName: _userName
    staticAdditionalField:
      _node_name: www013
    fieldTypes:
      _request_id: long

Properties

• enabled: Specify if logging to a GELF-compatible server should be enabled. Defaults to false;
• facility: The name of the application. Appears in facility column in the Graylog2 web interface. Defaults to the application name;
• host: The hostname of the Graylog2 server to send messages to. Defaults to "localhost";
• port: The port of the Graylog2 server to send messages to. Defaults to 12201;
• useLoggerName: If true, an additional field call "_loggerName" will be added to each GELF message. Its contents will be the fully qualified name of the logger. e. g. com.company.Thingo. Defaults to true;
• useThreadName: If true, an additional field call "_threadName" will be added to each GELF message. Its contents will be the name of the thread. Defaults to true;
• serverVersion: Specify which version the graylog2-server is. This is important because the GELF headers changed from 0.9.5 -> 0.9.6. Allowed values = 0.9.5 and 0.9.6. Defaults to "0.9.6";
• chunkThreshold: The maximum number of bytes allowed by the payload before the message should be chunked into smaller packets. Defaults to 1000;
• useMarker: If true, and the user has used an SLF4J marker in their log message by using one of the marker-overloaded log methods, then the marker.toString() will be added to the GELF message as the field _marker. Defaults to false;
• messagePattern: The layout of the actual message according to PatternLayout. Defaults to "%m%rEx";
• shortMessagePattern: The layout of the short message according to PatternLayout. Defaults to none which means the message will be truncated to create the short message;
• hostName The sending host name. Used to override the name of the server which will appear in the log messages. Defaults to the output of 'hostname';
• includeFullMDC: Add all fields from the MDC will be added to the GELF message. If set to false, only the keys listed in additionalFields will be added to a GELF message. Defaults to false;
• additionalFields: Add additional fields filled from the MDC. The key is the key of the MDC, the value is the key inside the GELF message. Defaults to empty;
• staticAdditionalFields: Add static additional fields. Defaults to empty;
• fieldTypes: Add type information to additional fields. Valid types:int, long, float, double. Defaults to string;

Maven Artifacts

This project is available on Maven Central. To add it to your project simply add the following dependencies to your POM:

<dependency>
  <groupId>net.gini.dropwizard</groupId>
  <artifactId>dropwizard-gelf</artifactId>
  <version>0.8.0-1</version>
  <!-- Make the Maven Enforcer plugin happy. -->
  <exclusions>
    <exclusion>
      <groupId>org.slf4j</groupId>
      <artifactId>slf4j-api</artifactId>
    </exclusion>
  </exclusions>
</dependency>

Support

Please file bug reports and feature requests in GitHub issues.

Acknowledgements

Thanks to Nick Telford for his initial version of the GraylogBundle.

Contributors

• Daniel Scott
• Michal Svab

License

Copyright (c) 2012-2013 smarchive GmbH, 2013-2015 Gini GmbH

This library is licensed under the Apache License, Version 2.0.

See http://www.apache.org/licenses/LICENSE-2.0.html or the LICENSE file in this repository for the full license text.